Chemistry Reference
In-Depth Information
MeS
MeS
O
O
O
O
Cl
3
CO
l
Me
N
Me
O
l
3
N
Me
Proton Sponge™ (
1
)
toluene, 70 °C
1. NaOH, DMSO
2. HCl, EtOAc
75% (3 steps)
MeS
O
Me
H
Scheme 8.2
Dealkylation of tertiary amine
The drastic effect of molecular sieves of 4A
(4A
MS) was reported by Ireland et al. [11].
Although, methylation of alcohol with Meerwein
s salt and Proton Sponge (1) in combina-
tion took placemuch faster than in the alternative protocol, the reaction stopped at about 50%
conversion in the case of alcohol, and decomposition of the spiroketal moiety was observed
Table 8.1
Alkoxylation of alcohol using Meerwein
s salt in the presence of Proton
Sponge (1)
Run
Alcohol
Oxonium Salt /Amine
Ether Product
Yield (%)
1
=
;
<
:
Me
3
OBF
4
(2.1 equiv)
Proton Sponge
(
Me
Me
69
1
) (2.1 equiv.)
Ph
OH
Ph
OMe
Me
Et
3
OBF
4
(1.5 equiv)
i
Pr
2
NEt (3.0 equiv.)
65
2
Ph
OEt
Me
<
:
3
=
;
Me
3
OBF
4
(1.0 equiv)
Proton Sponge
(
Me
Me
OH
57
Me
OMe
1
) (1.2 equiv.)
Me
Et
3
OBF
4
(1.0 equiv)
i
Pr
2
NEt (1.2 equiv.)
89
Me
OEt
4
